How would putting “unicycling” in the “skills”, “interests”, “hobbies”, or “activities” section of my CV be perceived? Would it help my chances at being accepted for a job or not? Could it possibly even harm my chances?
Whether it’s positive or not would depend on your prospective employer, but in general I think it’s positive. It’s a good conversation opener that you can use to promote yourself as determined, able to meet a challenge, etc.
Kris
I always have mountain unicycling on my CV. It sounds more interesting than just unicycling, which people will just mentally file under wacky circus skills.
I have been asked about it in almost every interview I’ve ever had, and have got a bunch of decent jobs over the years.
It is great. It
a)Gives you an easy question that you know the answer to.
b)Makes your CV memorable, so maybe more likely to be on an interview pile.
c)Makes the interviewer remember you - whilst this might have some chance of negative effects, anyone they forget has zero chance of getting a job.
d)Is a plausible source of anecdotes for when you are asked pointless rubbish like ‘tell me a situation when you had to show leadership skills’, particularly if you’ve run events / led rides and had to talk scared people off of big mountains or jolly up a team of people to avoid dropping out of some crazy race, or something like that, similarly for ‘tell us of a time when you had to sort out a problem’ or whatever other rubbish HR people ask you before you get a chance at talking to someone important.
I haven’t applyied for the sort of jobs where I will be expected to wear a suit every day mind, more computing / engineering / academic type jobs. I dunno how it’d come across for say a London bank, but I imagine that most unicycling types are also not working in a bank types?
Joe
Depends on the job.
It helped get me a job as a conselor at a summer camp because it was another skill that could reasonably be used on the job and it showed that I was outgoing and could perform.
It helped when I worked for a drug company because they thought I could juggle and ride at trade shows and such.
Some jobs, I think it might be a detractor. For instance, I DID NOT put it on my application to the US Naval Academy.
I added “competition orientated unicycling” in my CV. Well… i got the job and my boss wanted to know everything about it (i work as a network/server administrator).
So it cant be that bad 
Orientated? Oh, you’re in Germany. Your English is light years ahead of my Deutsch. 
Definitely mention unicycling for IT or similarly nerdy jobs (maybe not at executive level). It seems to be a great ice-breaker, and proves you don’t just live in a cyber-cave.
Using the word “unicycling” all by itself may have the wrong connotation though. It may lead some recruiters to think you waste your time on frivolous activities. That’s why the suggestion of “mountain unicycling” is a good one (assuming it’s true for you). If you have done specific, notable things with unicycling be sure to include those, such as:
- Extreme unicycling, formerly sponsored by Kris Holm Cycles
- Level 10 unicycle rider
- Unicycle racing/freestyle/hockey champion
- Former Guinness world record holder in unicycling
I picked up a new job last week and while unicycling wasn’t directly relevant to the job it turned out the business owner rides a uni.
When calling to tell me I got the job he was saying how I matched the company philosophy etc and he ended with…
‘and not that it should matter… but you unicycle!’ 
(I told my wife unicycling would be good for something one day!)
Regarding what to list in the ‘Interests’ section of a resume, whether it’s unicycling or whatever else just include things you’re genuinely interested in. If it helps, great, if it counts against you somehow you’re probably better off with another job.